A guillotine is an apparatus designed for efficiently carrying out executions by beheading. The device consists of a tall, upright frame with a weighted and angled blade suspended at the top. The condemned person is secured with a pillory at the bottom of the frame, holding the position of the neck directly below the blade. The blade is then released, swiftly and forcefully decapitating the victim with a single, clean pass; the head falls into a basket or other receptacle below.

The guillotine is best known for its use in France, particularly during the French Revolution, where the revolution's supporters celebrated it as the people's avenger and the revolution's opponents vilified it as the pre-eminent symbol of the violence of the Reign of Terror. While the name "guillotine" itself dates from this period, similar devices had been in use elsewhere in Europe over several centuries. Use of an oblique blade and the pillory-like restraint device set this type of guillotine apart from others. Display of severed heads had long been one of the most common ways European sovereigns exhibited their power to their subjects.

The design of the guillotine was intended to make capital punishment more reliable and less painful in accordance with new Enlightenment ideas of human rights. Prior to use of the guillotine, France had inflicted manual beheading and a variety of methods of execution, many of which were more gruesome and required a high level of precision and skill to carry out successfully. After its adoption, the device remained France's standard method of judicial execution until abolition of capital punishment in 1981. The last person to be executed in France was Hamida Djandoubi, guillotined on 10 September 1977.